Diagnosis:Cucullia dorsalis has been considered
a race or subspecies of speyeri. However there are small, but
consistent, differences in both superficial appearance and the male genitalia.
The ranges of the two species appear to overlap marginally on the eastern
edge of the Rocky Mountains, although the locality of the overlaping specimens,
"Denver", is too vague to guarantee sympatry. A second area
of possible sympatry is in southern Washington. Cucullia dorsalis
is darker and the markings are more strongly etched with black than in
speyeri, and the forewing anal dash is stronger and more likely
to reach the postmedial line. The right clasper of the male genitalia
is much smaller than it is in speyeri. The right and left valves
are fairly symmetric in appearance, although the right clasper is still
slightly larger than the left.

The ranges of dorsalis and laetifica overlap in southwestern
Colorado. The two species in this region can be very difficult to separate
superficially. In general dorsalis is larger and a more uniform
gray color than laetifica. Cucullia laetifica often
has a slightly bluish cast about it. Also the median area of the forewing
in laetifica often has lighter area preceeding the postmedial
line where it intercepts the anal dash. The claspers of the right and
left valves of the male genitalia are almost equal in size in dorsalis,
but the right clasper is markedly larger than the left in laetifica
(compare the photos of the male genitalia). Wing length from base to apex:
mean = 22.55 mm., standard deviation = 1.48 mm., n = 10.

Distribution:Cucullia dorsalis is a species
of the western Rocky mountains and the Great Basin area. It has so far
been found in most of Colorado except the far eastern part of the state,
north to southern Washington, western Wyoming, northern New Mexico and
Nevada, northern Arizona, Utah, and central California. There does not
appear to be any significant variation either geographical or individual
in dorsalis other than the sexual dimorphism in hindwing wing coloration
typical of the group.

Adults have been collected from May to August.

Identification Quality: Excellent

Larva: Unknown

Foodplants: The larva of this species has not been described.
There are two adult specimens from California in the USNM reared from
Machaerantha shastensis, an herbaceous composite, but no associated
larvae. There is also a single female from Weld County, Colorado reared
from Helianthus sp. (Asteraceae). Crumb's (1956) "Cucullia
#8" may be this species. It belongs to the group and is most similar
to speyeri but has an isolated anterior dorsal yellow marking
as in laetifica.